Nationals let another one slip away

You’re not going to win every game. Nobody does. But when you’ve got significant ground to make up and not a lot of time to do it, you can’t afford to give away games that were there for the taking.

Which is exactly what the Nationals have done too many times over the last month, culminating with Monday night’s latest gut-punch: an 8-5 loss to the Cardinals that included all kinds of failed execution at critical moments late.

When Ryan Zimmerman launched a 3-run homer off Kevin Siegrist in the top of the seventh, there was for a moment as much of a positive vibe surrounding this team as there had been in a really long time. Zimmerman’s blast — which gave him 28 RBI for the month, tying a club…